1. Field of the Invention
The field of the invention generally relates to infrared control systems and in particular to such systems and components thereof that are interference resistant.
2. Description of the Related Art
Infrared (“IR”) control systems are increasingly being employed to govern or otherwise manipulate a wide spectrum of user interactive home and office electrical and electromechanical components and appliances. Today, almost all conventional audio and video components, such as televisions and stereo equipment as well as more recently developed technologies such as satellite dish tuners, digital video disc players (DVD players), and electronic video recorders include IR control systems. Moreover, such systems are increasingly being used to govern the function of home and office fixtures, such as window blinds and lighting; mechanical systems, such as heating, ventilation and air conditioning; and even traditional appliances, such as automated coffee machines and dishwashers.
IR control systems are now so commonly employed, that a casual stroll through a contemporary home or office environment would no doubt reveal numerous IR remote controls scattered about, virtually in every room. Although offering much in the way of convenience to the user, the success and acceptance by the consumer of IR control systems has ironically created derivative inconveniences.
For example, one might only recall the number of times a remote control for the television was mistakenly employed, without success, to control the video player or visa-versa. One reason for the lack of operability is that manufacturer supplied IR controls are typically narrow-band tuned and therefore product or component specific. An example of such a tuned system is described in U.S. Pat. No. 3,928,760 issued to Mikio Isoda, which is hereby incorporated by reference. As described in U.S. Pat. No. 3,928,760, a traditional narrow-band tuned IR remote control system employs a handheld transmitter and a stationary receiver. The transmitter comprises a modulating circuit and an electroluminescent diode, which upon being energized emits short pulses of IR light encoded with data. The wavelength of the IR light emitted is defined by the inherent characteristics of the electroluminescent diode, whereas, the modulating circuit governs the modulation or frequency (e.g., 40 KHz) of the light emitted from the diode. The receiver comprises a detector, which detects impinging IR light signals and an amplifier. The amplifier is “tuned” or configured to respond to the frequency of the light emitted from the diode (e.g., 40 KHz) and functions to amplify and transmit that signal to additional control circuitry, which demodulates the data stream and controls the operation of the device. Consequently, because manufacturers typically employ IR control systems that are tuned on a product-by-product basis to a chosen narrow-band frequency, a tremendous amount of variation exists among control systems.
The inability to control a component outside the line-of-site or beyond the transmission range of the component's IR receiver—such as when the component is in another room, represents yet another inconvenience to the user. Recognition of the foregoing inconveniences has driven the industry to develop new technologies.
For example, universally adaptable IR remote control transmitters, such as that disclosed in U.S. Pat. No. 4,626,848 issued to Raymond G. Ehlers, which is hereby incorporated by reference, facilitate the transmission of IR signals having suitable frequency and wavelength to be capable of controlling numerous components made by different manufacturers. As such, the inconvenience of seeking out multiple controllers may be significantly alleviated.
In addition, IR extension or repeater systems, such as that disclosed in U.S. Pat. No. 4,509,211 to Michael S. Robbins, which is hereby incorporated by reference, have also significantly improved the usability of IR control systems. IR extension or repeater systems are capable of allowing the user to control one or more various components, even though its physical location is remote or outside the line-of-site or range of the transmitter, thereby providing a remote link to the component. They are generally comprised of a receiver, capable of detecting the IR signal and amplifying the signal, and a transmitter, which “repeats” or retransmits the signal, for example into another room, thereby “extending” or “repeating” the signal.
Over the years, such IR repeater systems have found wide acclaim among consumers. So much so that it is not uncommon for contractors to install such systems into new and remodeled homes and offices, as was the case for indoor plumbing and electrical wiring at the turn of the twentieth century.
Despite these improvements, one shortcoming that has consistently plagued the industry from achieving the full benefits of IR control has been the stark absence of a suitable generic or wide-band IR receiver capable of being used in extension or repeater systems. That is, an IR receiver that is both capable of detecting a wide-band of IR frequencies and wavelengths so as to be compatible with a wide variety of IR controlled components while maintaining sufficient selectivity so as to be operable in the presence of conventional IR noise or interference.
While in the past concern relating to IR noise was generally limited to ambient lighting such as sunlight or artificial light sources, such as fluorescent lamps, the IR emission from plasma televisions, now so readily found in homes and offices, has compounded the concern. That is so, because not only do plasma displays have the capability of emitting a significant amount of IR radiation, they also are often positioned in close proximity to extension or repeater systems, thereby exacerbating their effect.
As a result, with the advent of plasma televisions and the proliferation of multitudes of IR controlled components and appliances, the industry and users alike have for years been frustrated with the absence of a suitable interference resistant broadband receiver for use in conventional IR control systems.
It can be seen, then, that there is a need in the art for a wideband IR receiver that is resistant to interference from stray IR radiation. It can also be seen that there is a need in the art for a wideband IR receiver that is resistant to stray IR radiation interference that can be utilized in a repeater configuration.